Guitar tuner



Jan. 27, .1970 R. c. JERANSON 3,491,644

GUITAR TUNER Filed Nov. 18, 1966 INVENTOR.

. JERANSON ATTORNEY United States Patent 3,491,644 GUITAR TUNER Richard C. Jeranson, 5800 69th Ave. N., Brooklyn Park, Minn. 55007 Filed Nov. 18, 1966, Ser. No. 595,403 Int. Cl. Gd 3/14 US. Cl. 84312 4 Claims ABSTRACT OF THE DISCLOSURE A tuning device for a stringed instrument comprising a housing which incloses a cam and follower. The follower is connected to a rod rotatably mounted within the housing so that movement of the cam causes a rotation of the rod. The strings are connected to the rod by levers which extend radially from the rod and are threaded through the rod.

This invention relates to a device which may be attached to a guitar and may be operated to selectively tighten or loosen each guitar string in such a way as to quickly and easily change the tuning of the guitar.

A typical six-string guitar is constructed with a large resonator with a long wooden neck extending from one end of the sound box. The strings on which the music is played are usually fastened to the base of the resonator, which is the end farthest from the neck. The strings then extend from the base to six rotatable pins at the end of the neck most distant from the base. Each string may then be tightened or loosened by turning the rotatable pins at the end of the arm. By rotating the pins one can obtain dilferent tensions in each string. There are also a number of raised cross pieces called frets on the neck of the guitar. The strings may be depressed at any point along the neck so that the strings make contact with one of the frets. By selectively depressing the strings along the neck one can vary the effective length of the string. Music is produced #by plucking the strings of the guitar. The tone of each plucked string is determined by the tension in the string and by th length of the string.

In these guitars, the tension of each string must be set by a tedious process of alternately plucking the strings and turning the rotatable pins. Once the tension is estabished the length of the string and therefore the tones that may be produced on the instrument are determined solely by the positions of the raised cross pieces on the neck. As a result there are a determined and limited number of notes or tones that can be produced with a guitar in a given tuning.

It may be desired by a guitarist to play a melody on his guitar with the guitar tuned in a first tuning or key, such as for western music. He may then only a short time later, desire to play a melody on a guitar in a second tuning or key such as for Spanish music. At present, tuning devices used for this purpose are complex, bulky, and expensive. This invention provides a simple, compact and inexpensive tuning device.

The same problems arise with other stringed instruments such as a banjo or ukele.

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An object of this invention is to provide a device whereby a guitar may be quickly and easily tuned to either of two different tunings.

A further object of this invention is to provide guitars and other stringed instruments with a greatly increased number of notes which may be produced.

FIGURE 1 is a top-plan view of a typical guitar With a guitar tuner of this invention attached;

FIGURE 2 is a side-elevational view of the guitar tuner of this invention;

FIGURE 3 is a front and elevational view of the guitar tuner of this invention;

FIGURE 4 shows the guitar-string hook which is used to attach the strings to the guitar tuner of this invention;

FIGURE 5 shows a threaded lever used in the guitar tuner;

FIGURE 6 shows a side-elevational view of a first alternative form of this invention;

FIGURE 7 shows a side-elevational view of a second alternative structure of this invention;

FIGURE 8 shows a side-elevational view of a fourth alternative structure of this invention;

FIGURE 9 shows a side-elevational view of a fifth alternative structure of this invention.

Referring to the drawings and the numbers of reference thereon, in FIGURE 1 the typical guitar 10 has a large sound box 17 with a neck 13 extending from one end thereof. The strings 15 extend from rotatable pins 14 at the end of the neck, across a sound box 17 to the guitar tuner 20. The guitar tuner is rigidly attached to a base plate 18 which is fastened to the base 12 of the guitar.

The guitar is played by plucking the strings either individually or in unison to produce a chord. The tone produced by each string may be adjusted in three ways. The tension in each string may be adjusted by rotating the rotatable pins 14 and either tightening or lossening each individual string. While the guitar is being played, each individual string 15 may be depressed with a finger against a fret 16 which in effect shortens the length of the string. The effective length of the string is the distance between the bridge 28 over which each string passes and the raised fret 16 which each string touches. With the guitar tuner of this invention the tension and therefore the tone of each string may be quickly changed by rotating the tuning lever 19.

The structure and operation of the tuner can perhaps be the best seen in FIGURE 2. The tuner 20 is enclosed in a housing 29. The housing is broken away to show the general structure of the tuner. The tuning lever 19 is attached to a rod 21 running through the housing from top to bottom perpendicular to the face of the guitar. A cam 22 is mounted on the rod 21.

A follower 27 is rigidly attached to one end to a spur gear 24. The other end of the follower 27 is free and is situated so as to ride on the cam 22 as the tuning lever 19 is turned. A spur gear 24 is mounted on a rod 23 with an axis running from one side of the housing 29 to the other side with an axis perpendicular to the axis of the cam 22.

A plurality of threaded levers 25 are mounted on rod 23. Each threaded lever 25 is mounted in a threaded hole in rod 23. The length of each threaded lever 25 may be adjusted by screwing the lever up or down, through the hole through rod 23. The guitar strings are attached to the threaded levers by means of a string hook 26.

The tension on the strings 15 tends to rotate a spur gear 24, as shown in FIGURE 2, in a clockwise direction. This in turn holds follower 27 firmly against the cam 22. Thus when tuning lever 19 is turned cam 22 forces follower 27 to rise or fall. This in turn causes spur gear 24 to rotate in a counterclockwise or clockwise direction, which in turn tightens or loosens string, respectively the strings 15.

A second spur gear with associated rod, levers and string hooks is placed in meshing relation with the first spur gear 23. When spur gear 23 rotates in a clockwise direction spur gear 30 then rotates in a counterclockwise direction, and vice versa. Thus when strings attached to the threaded levers associated with spur gear 24 tighten, strings attached to threaded levers associated with spur gear 30 are loosened, and vice versa.

Further, it may be seen in FIGURE 3, the rod 23 may be cut away near some of the threaded levers such as at point 47 so that the guitar string may be mounted near the center of rod 23 and its tension will not be changed when the rod is rotated. Thus when rod 23 is turned, the string is not loosened or tightened. Thus, the guitar tuner of this invention may be adjusted to individually tighten or loosen or leave unchanged each string of the guitar when the tuning lever is turned. The amount that the string is tightened or loosened in any case is adjusted by setting the threaded levers by turning them either up or down in the threaded holes.

The position of the cam for the two different tunings may be selected so that the greatest torque from the string tends to rotate the follower against the cam. This holds the follower against the cam so that only a single contact is needed and no spring need be used.

The manner in which the guitar strings are attached to the threaded levers is shown in FIGURES 4 and 5. The string hook 26 has a small hole 31 near one end to which the guitar string is tied. Near the other end is a keyhole slot 32 comprising a round hole 33 somewhat larger than the outside diameter of the threaded lever, and a narrower elongate slot 34. The threaded lever 25 has an Allen head 35 or other means of turning it. At some predetermined position along the shank, usually near the end farthest from the Allen head, is a cut or reduced section 36. The reduced section has a diameter of approximately onehalf of the outside diameter of the threaded lever.

In operation, the string is attached to the threaded lever in the following manner. The rotatable pin 14 of FIGURE 1, is rotated loosening the guitar string 15. The end of the guitar string is then fastened by tying it through the hole 31 in string hook 26. The threaded lever 25 is fixed in operating position on rod 23 of FIGURE 2. String hook 26 is then attached to the threaded lever by inserting the end of the string hook through the threaded lever 25. It is then released and the reduced section 36 slides in to the slot 34 of the string hook 26. The rotatable pin 14 may then be tightened to draw the string up to the desired tension.

Once the string is attached to the threaded lever, and the guitar is tuned to one desired tuning, the tuning lever 19 may then be turned to a second position. The guitar may then be tuned as desired in the second position by turning the threaded screws 25 to tighten or loosen the respective strings and produce the desired tone. The guitar may be then tuned quickly to either of the two tunings by turning the tuning lever 19.

If a cam as shown at 22 with a single inclined plane of about one-half a turn is used, then the two tunings of the guitar are precisely determined by the two level areas of the cam, and theycan always be reached with great accuracy when tuning the guitar. If a cam without precisely determined levels is used, stopping pins 37 may be employed as shown in FIGURE 6. When tuning lever 19 rests against either of the two stopping pins 37, the

guitar will be precisely tuned to one of the two desired.

tunings.

If more of the strings are attached to the rod associated with the front spur gear 30 than are attached to the back spur gear 23 as shown in FIGURE 2, so that the net torque on spur gear 23 is counterclockwise, the gears will tend to rotate in such a manner as to prevent follower 27 from riding tightly on cam 22. Accurate tuning would then not be possible. It may then be necessary to use a multilevel cam 41 as shown in FIGURE 6. Such a cam will hold the follower 27 firmly between two levels of the cam. Then, whether the guitar strings tend to force the follower 27 to rise or fall, when the tuning lever 19 is turned the follower and therefore the spur gears will turn as desired.

A second modified form of the invention is shown in FIGURE 7. In this modified structure, a finely geared worm gear 43 is attached to the tuning lever 19. Two worm wheels 44 and 45 are located one on each side of the finely geared worm gear. The associated rods, threaded levers, and string hooks are similarly placed on opposite sides of the finely geared worm gear. Again when the tuning lever 19 is turned the worm wheels turn in opposite directions and the guitar strings are selectively tightened or loosened as in the early forms of the invention.

A third modification of the invention, shown in FIG- URE 8, employes the basic structure discussed originally. However, a compression spring 46 is placed between the top of the housing 29, and follower 27. In this way the follower is forced to remain against the face of the cam and tuning accuracy is maintained.

A fourth modified form of the invention is shown in FIGURE 9. In this structure a single rod 48 is used for mounting the levers. To provide selective tightening and loosening of the strings when the rod rotates, the levers 49 are constructed to extend from either the top or the bottom of rod 48. The threaded lever 25 of FIGURE 5 is ideally suited to this purpose. It may be threaded through the hole in rod 48 to extend either above or below. In operation, when tuning lever 19 is turned, cam 22 r'otates. Follower 47 then rises or falls in response to the rotation of the cam. This in turn causes rod 48 to rotate either counterclockwise or clockwise. When rod 48 rotates clockwise, the bottom end of lever 49 moves toward the neck of the guitar, thus loosening strings attached to that end. At the same time, the top end of lever 49 moves in the opposite direction, thus tightening strings attached to it. By selecting the end of the lever to which the strings are attached, and by adjusting the length of the levers, any desired tuning may be accomplished.

In the form of the invention shown in FIGURE 9, some strings are attached near the top end of the levers. This may raise the string off the bridge 28 of FIGURE 1, and thus completely destroy the tuning. To prevent this, the housing 50 may be turned down in front to provide a straight edge 51, holding the strings down tightly against the bridge.

The guitar tuner described in this invention provides economic, low cost device for quickly, easily and accurately adjusting the tuning of a guitar or other stringed instrument.

The Word guitar as used in these specifications and claims is understood to mean any string instrument including but not limited to guitar, banjo and ukulele.

What is claimed is:

1. A tuning device comprising:

a housing;

a cam rotatably mounted in said housing;

a first rod rotatably mounted in said housing;

means for rotating said rod in response to a rotation of said cam;

a plurality of levers extending radially from, and

spaced axially along said rod, and;

means for attaching each of said levers to a string on a musical instrument so that the rotation of said cam selectively varies the tension on the strings so as to change the tuning of the instrument.

2. The apparatus of claim 1 wherein said levers are threaded and extend through threaded passages in said rod so that the length of said levers extending through the threaded passage may be varied by rotating said levers.

3. The apparatus of claim 1 wherein a second rod is rotatably mounted is said housing, and further means is provided to cause said second rod to rotate in an opposite direction from the first rod when said cam is rotated.

4. The apparatus of claim 3 wherein a first gear is attached to said first-rod and a second gear is attached to said second rod so that said first gear and said second gear are in a meshed relationship.

References Cited UNITED STATES PATENTS 1,883,410 10/1932 Ryan 84312 3,162,083 12/1964 Webster 84313 RICHARD B. WILKINSON, Primary Examiner I, F. GONZALES, Assistant Examiner 

